I've tried AVG and it's good. It's user-friendly and you can also schedule regular scans on your phone. I use it on my two Android devices. You can always download the free trial version and see if you like it.
You can try Avast or AVG. I chose this for it has a good reputation when it comes to Anti-virus in Personal Computers. So I pretty assume that it works just as fine in your android devices. But I currently use the pre-installed smart manager in my Samsung Phone. My reason is that why a phone brand would install a security feature in their specific phone model if it is not the best security tool for it?It works great from the time I first used it up until now.
I'm also an Avast user. I strongly recommending avast for android. It's perfect anti-virus. Not just it protect your phone but also maximize it. My phones runs smoothly with avast in it. Try it and Avast will not disappoint you.